LXR linux/arch/mips/loongson64/loongson-3/cop2-ex.c

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 2014 Lemote Corporation.
   7 *   written by Huacai Chen <chenhc@lemote.com>
   8 *
   9 * based on arch/mips/cavium-octeon/cpu.c
  10 * Copyright (C) 2009 Wind River Systems,
  11 *   written by Ralf Baechle <ralf@linux-mips.org>
  12 */
  13#include <linux/init.h>
  14#include <linux/sched.h>
  15#include <linux/notifier.h>
  16#include <linux/ptrace.h>
  17
  18#include <asm/fpu.h>
  19#include <asm/cop2.h>
  20#include <asm/current.h>
  21#include <asm/mipsregs.h>
  22
  23static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
  24        void *data)
  25{
  26        int fpu_owned;
  27        int fr = !test_thread_flag(TIF_32BIT_FPREGS);
  28
  29        switch (action) {
  30        case CU2_EXCEPTION:
  31                preempt_disable();
  32                fpu_owned = __is_fpu_owner();
  33                if (!fr)
  34                        set_c0_status(ST0_CU1 | ST0_CU2);
  35                else
  36                        set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
  37                enable_fpu_hazard();
  38                KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
  39                if (fr)
  40                        KSTK_STATUS(current) |= ST0_FR;
  41                else
  42                        KSTK_STATUS(current) &= ~ST0_FR;
  43                /* If FPU is owned, we needn't init or restore fp */
  44                if (!fpu_owned) {
  45                        set_thread_flag(TIF_USEDFPU);
  46                        if (!used_math()) {
  47                                _init_fpu(current->thread.fpu.fcr31);
  48                                set_used_math();
  49                        } else
  50                                _restore_fp(current);
  51                }
  52                preempt_enable();
  53
  54                return NOTIFY_STOP;     /* Don't call default notifier */
  55        }
  56
  57        return NOTIFY_OK;               /* Let default notifier send signals */
  58}
  59
  60static int __init loongson_cu2_setup(void)
  61{
  62        return cu2_notifier(loongson_cu2_call, 0);
  63}
  64early_initcall(loongson_cu2_setup);
  65